Procalcitonin predicts patients at low risk of death from community-acquired pneumonia across all CRB-65 classes

¹ Dept of Internal Medicine II, University Hospital Ulm, Germany
² Thoraxzentrum Ruhrgebiet, Kliniken für Pneumologie und Infektiologie, Ev. Krankenhaus Herne und Augusta Kranken-Anstalt Bochum, Germany
³ Dept of Medical Microbiology and Hygiene, University Hospital Ulm, Germany
⁴ Research Department, BRAHMS AG, Hennigsdorf, Germany
⁵ CAPNETZ study centre, University Hospital Ulm, Germany
⁶ Dept of Internal Medicine/ Infectious Diseases and Pulmonary Medicine, Charite, University Medicine, Berlin, Germany
⁷ Dept of Pneumology, Hannover Medical School, University Clinic Hannover, Germany

^* To whom correspondence should be addressed. E-mail: welte.tobias{at}mh-hannover.de.

	Abstract

Aim of this study was to investigate the prognostic value of procalcitonin (PCT) compared to the established inflammatory markers C-reactive protein (CRP) and leukocyte count (WBC) alone and in combination with the CRB-65 score in patients with community acquired pneumonia (CAP).

We enrolled 1671 patients with proven CAP. PCT, CRP, WBC and CRB-65 score were determined on admission. Patients were followed-up for 28 days for survival.

In contrast to CRP and WBC, PCT levels markedly increased with the severity of CAP as measured by the CRB-65 score. In 70 patients who died during follow-up, PCT levels on admission were significantly higher compared to levels in survivors. In ROC analysis for survival, the AUC for PCT and CRB-65 was comparable (0.80, 95% CI 0.75–0.84 vs. 0.79, 95% CI 0.74–0.84, n.s.), but each significantly higher compared to CRP (0.62, 95% CI 0.54–0.68, p<0.01) and WBC (0.61, 95% CI 0.54–0.68, p<0.01). PCT indentified low risk patients across CRB-classes 0, 1 and 2 as well as 3 and 4.

In conclusion, PCT levels on admission predict the severity and outcome of CAP with a similar prognostic accuracy as the CRB-65 score and a higher prognostic accuracy compared to CRP and WBC. PCT can independently identify patients at low risk of death within CRB-65 risk classes.

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